Is it permissible for the heirs to sell the incomplete apartments and the land that their mother bequeathed as an endowment, and what is their share and their mother’s share from this bequest, knowing that they do not have sufficient money to complete the construction and are seeking to purchase a ready-made dwelling and endow it on behalf of their mother?

A will for an endowment (waqf) is valid, and it is limited to one-third of the estate. Any amount exceeding this one-third is contingent upon the heirs' approval. In accordance with the will of Umar ibn al-Khattab (may Allah be pleased with him), the heirs are not obligated to construct buildings on the land or to distribute the excess beyond one-third equally. Rather, they are obligated to distribute it according to the prescribed Islamic division (qisma shar'iyya), unless they choose to make the entire property an endowment. If the testator intends to endow the apartments to the heirs, then it is an endowment for the descendants. If she intends for them to own the apartments, then it is not an endowment. If the endowment is binding, it is only binding for one-third, and the heirs benefit equally from the remainder. The remaining two-thirds are divided among them as inheritance. If it is not possible to benefit from one-third of the building and land, then it should be sold, and a dwelling should be purchased with the proceeds to be an endowment. Two sacrifices (udhiyah) should be made from its rent, and the remainder should be divided among the heirs. In summary: The will is only binding for one-third of the estate. The heirs have the choice regarding the remaining two-thirds either to make them an endowment or to divide them as inheritance. It is advisable to consult the Sharia court.